Growth Computations Rates of growth in natural sawtimber stands were computed by Schneider's formula: P = 400 in which P = estimated annual growth percent n = number of growth rings in last inch of radius d = present tree DBH in inches. This formula is not recommended for all conditions, but was chosen in the present instance because of its simplicity and ability to yield satisfactory results in preliminary studies of growth in mature forests. Average tree diameter by species was obtained as a part of the inventory, and number-of-rings-per-inch data were secured from log and stump sections. Most Chilean species were found to be too hard to penetrate readily with an increment borer. Rates of growth in immature natural forests and in forest plantations are based on direct samples of mean annual increment per unit of area in typical even-aged stands at or or near probable rotation age. Such growth plots were taken in planted stands from 9 to 43 years of age, in natural stands from 25 to 130 years of age. Summaries of the findings on these plots are given on appendix pages 213 and 214. Growth rates actually applied to the inventory of the immature forest areas were discounted to allow for under stocking inevitable over broad areas. Other data used in estimating rate of growth in plantations were obtained from: Konrad Peters, "Estudio Experimental Sobre Silvicultura en Chile"; Imprenta Nascimento, Santiago, Chile, 1938, plantation owners or their representatives; and Fomento foresters. DERIVATION OF REQUIREMENTS VALUES Requirements values were obtained primarily from Census statistics, by personal interview or letter questionnaire, or from authoritative studies made by agencies of the Chilean Government or engineering associations or similar bodies. Estimates of future requirements are necessarily speculative. The principal steps used in arriving at these values are outlined under individual parts of this section. Fuelwood No Census data are available on the use of wood as fuel except for railroad statistics, showing the shipments of fuelwood and charcoal to Santiago for the 1941-43 period. Census data are available on the use of charcoal and wood for industrial purposes, and on the number of gas installations in Santiago and other large cities where this fuel has been substituted for wood by domestic consumers. It was necessary to arrive at a value for present consumption by an estimate based on the opinion of wood-users, dealers, Census officials, and so on, checked against consumption in Santiago by individual consumers on the basis of rail shipments plus 10 percent for fuel brought in by truck and cart. Values arrived at in this way were checked for reasonability against other values for world consumption and adjusted for various forest zones and urban versus rural use, taking into consideration cooking and heating necessities, as these vary from place to place. The resulting figure, showing a total per capita consumption of 29.2 cubic feet per year, checks reasonably well with other countries. Chile shows a larger value than countries like France, Germany and Spain, exten where fuel is either very scarce or substitutes such as coal sively used, and less consumption than in countries like Norway, Sweden, or the United States where wood is abundant and used fairly freely. If per capita consumption is figured on the amount used by wood-burners only, this is estimated to average some 34.7 cubic feet per capita in Chile as against 96.0 cubic feet per capita in the United States. The writers believe this a reasonable estimate, in view of climatic conditions and habits of wood use, between Chile and the United States. Accordingly, the present estimate for fuelwood consumption, which is somewhat larger than that reached by Dr. Krassa but considerably lower than other previous estimates based on fuel consumption studies, is believed to be reasonably accurate. Fencing and Minor Agricultural Use No Census statistics are available on the amount of wood used for posts, fencing, and minor agricultural use, and these estimates are based primarily on field observations and the opinion of agriculturists and agricultural officials. In brief, these figures are built up on a basis of an estimate of the number of new farms needing fencing and other materials (based on Census statistics as to the number of new farms per year up to 1936). The amount and character of fencing and other use by province zone, and the percentage of various types of fence with corresponding estimates of the amount of wood employed in each, were used in deriving the values for wood used in fencing. For wire fencing, a rough check is available in the amount of wire imports. Statistics are also available for vineyard posts and poles. To the values thus derived for new construction were added estimates covering repairs and replacements. Experience elsewhere has indicated that these were relatively small as compared with new construction in a period of farm increase such as Chile is now undergoing. Lumber and Lumber Products Census statistics are available for lumber and lumber products and are regarded as reasonably accurate from the year 1936. However, as these statistics are gathered by questionnaire, it is probable that they are conservative because many small mills are not reporting. According to these figures, Chile consumes about 209 million board feet annually, or 41.8 board feet per capita, based on an estimated 5 million population in 1944. Per capita consumption on this basis is about equal to that in Argentina (38 board feet) and larger than that in France and Mexico (30 and 10 board feet, respectively), but considerably less than per capita consumption in other countries with a substantial forest resource such as the United States, Norway and Sweden (245, 180, and 195 board feet per capita respectively). Lumber for Construction Lumber for construction is estimated at 126 million board feet annually. This figure is derived partly on the basis of available statistics, partly by estimate. Census values are available showing the number, type, surface area, and value per unit area for all construction in 13 principal municipalities, and these values for the years 19361943, inclusive, have been used as a basis for urban construction figIt was estimated that these statistics covered 80 percent of total urban construction, and the estimates for wood use adjusted accordingly. Values were then obtained, showing the number of board feet per square meter for various types of construction, these figures being de ures. rived from architects and various government housing agencies. The future building program is assumed to follow the same trends as in the past several years as to types of buildings and percent of each. Accordingly, the number of each type of building multiplied by the wood used per unit furnished a value for annual consumption for urban construction of all kinds. No similar values were available for rural housing. However, Census figures do show the area increase and number of farms up to 1936, and competent agriculturists believe that this trend will continue indefinitely over the next several decades. Accordingly, an estimate based on the opinion of competent agriculturists and government officials was made as to the number of new farm units actually developed as farms (one-third), and similar estimates were prepared on the amount of wood used in farm residences and other buildings in various province zones, these being checked where possible against architects' estimates, construction records of the Caja de Colonizacion, and so on. Similarly, estimates were obtained as to replacements and repairs on established farms. No claim can be made as to exactness. However, when the total value for wood used in construction derived in this way was checked against the percentage of the total lumber cut estimate, as used for construction by leading lumber dealers, it came within 2 percent, as was true also when the percentage used for construction was added to the percentages estimated independently as used for other lumber items and these totaled to check the entire value as obtained from Census statistics. Accordingly, it is believed that these figures are reasonably accurate and satisfactory for the uses to which they are put here. Lumber for Factory Use No Census statistics are available on the consumption of lumber for factory use, i.e., such items as boxes and crates, furniture, shingles, etc. However, independent estimates obtained by questionnaire and personal interview from lumber dealers and manufacturers in these fields all checked reasonably well when totaled to account for the entire sawmill cut. Other Values Other values for individual consumption fields were derived as indicated under the appendix section on cutting depletion methodology. In converting volumes in board and cubic feet for table 28 (Estimated Timber Requirements: Present and Future), the board foot volumes were first converted to cubic feet by means of an average board foot-cubic foot ratio of 0.25, i.e. Board Feet X 0.25 cubic foot equivalent. This value is then expressed in terms of tree volume. Ten percent was then added to cubic volumes, to convert to tree volume, this being done for primary as well as secondary depletion values to simplify the presentation of future values. These values were then totaled and converted to primary, using 85 percent as the best estimate for percentage of primary in 1944 to 1954 and 90 percent for future (1970). increases were then figured in terms of primary values as the best indication of future demands versus growth. The Alerce Volume Table, International 1/4-Inch Rule Based on d.i.b. of average log equals 63 percent of d.b.h., o.b. Average stump height equals tree diameter at breast height. Top diameter is that at the point of normal utilization for sawtimber, which ranges from about 40 to 60 percent of d.b.h., averaging about 50 percent. Volumes shown are gross log scale, from which necessary deductions for defect should be made. |